Question

How much work will be done in making a soap bubble of diameter 2.0 cm ?

Ans. 7.54 × 10^-5 J​

Answer 1

Answer:

• Work Done (W) in Making A Soap Bubble is 7.54 x 10⁻⁴ Joules.

Given:

1. Diameter of Soap Bubble (D) = 2.0 cm.

Explanation:

$\rule{300}{1.5}$

Firstly Finding The Area of Soap Bubble:-

As Soap is Circular,

Area of Circle (Soap) = 4πr²

Substituting the Values,

• D = 2 cm ; r = 1 cm = 1 x 10⁻² m (S.I Unit)

⇒ Area (A) = 4 x 3.14 x (1 x 10⁻²)²

⇒ Area (A) = 4 x 3.14 x 1 x 10⁻⁴

⇒ Area (A) = 12.56 x 1 x 10⁻⁴

⇒ Area (A) = 12.56 x 10⁻⁴ m².

$\rule{300}{1.5}$

$\rule{300}{1.5}$

From The Formula,

⇒ W = T. ΔA

As The Soap Bubble As Two Surfaces, Then the Equation Becomes.

W = T . 2 x ΔA

Substituting the Values,

⇒ W = 3.0 x 10⁻² x 2 x 12.56 x 10⁻⁴

• Surface Tension of Soap Bubble is  3.0 x 10⁻² N/m.

⇒ W = 3 x 2 x 12.56 x 10⁻⁴⁻²

⇒ W  = 6 x 12.56 x 10⁻⁶

⇒ W = 75.36 x 10⁻⁶

⇒ W = 7.536 x 10⁻⁵

Rounding Off to Nearest Digit.

⇒ W = 7.54 x 10⁻⁵ J.

∴ Work Done (W) In Making A soap Bubble is 7.54 x 10⁻⁵ Joules.

$\rule{300}{1.5}$